Hosital signaling switch



Oct. 31, 1950 c. MILLER 2,527,564

HOSPITAL SIGNALING SWITCH Filed April 9, 1947 2 Sheets-SheetQ INVENTOR CHFP/ST/A/V M/LLLV'? WWW ATTORNEY Patented Oct. 31 1950 HOSPITAL SIGNALING SWITCH Christian Miller, Norwalk, Conn., assignor to Ed'- wards & Company, Inc., Norwalk, Conn., a corporation of New York Application April 9, 1947, Serial No. M0288 7 Claims.

This invention relates to hospital signalling switch construction, more particularly to a switch construction intended to be operated by a bed patient for signalling or calling an attendant.

One of the objects of this invention is to provide a compact and stron switch construction that will be convenient for actuation by a patient for setting it to effect the calling signals and that will be simple and dependable for release from its set or actuated condition by the answerin attendant. Another object is to provide a switch construction of the above mentioned kind that will embody features of construction whereby it can be quickly and easily adapted for various kinds of control or actuation by the patient. For example, there are circumstances where it is appropriate and convenient for the patient to set the switch by a simple exertion of pressure as by actuating a push button and there can be circumstances where the patient is incapable of exerting a manual pressure, being, for example, physically incapacitated so to do, but can exert a pull as on a string, chain or the like, and hence this invention aims also to provide a signalling switch construction of such flexibility of rearrangement of its parts that it can be easily and quickly suited to meet such varying conditions or requirements of practical use. More particularly another object is to provide a switch construction operable either by a push or tension member and so constructed that its parts can be readily rearranged by the attendant to suit a particular requirement and at the same time avoid any elements of confusion as to how the patient is to operate the device.

Another object is to provide an improved selflocking switch construction with improved means for releasing it from set or locked condition. Another object is to provide a switch of the above-mentioned kind with locking and release mechanism that will be simple and inexpensive to manufacture and assemble, of reliable action, and constructed and arranged, with respect to the main actuating element, that the operator, such as a patient, has minimum or no material opportunity or risk of confusing the release mechanism with the main actuatin element. Another object is in general to provide an improved signalling switch construction capable of handlin a number of signalling circuits, and other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements} and arrangements of parts as will be exempli fied in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown a preferred embodiment of this invention, Figure 1 is a small scale side elevation of the switch with a multi-conductor cable associated therewith showing the switch arranged for pushbutton operation;

Figure 2 is a plan view as seen from the top in Figure l; Figure 3 is a central vertical sectional view on an enlarged scale asseen along line 3-3 of Fi ure 2, certain parts bein shown in elevation;

Figure 4 is a central vertical sectional view as seen along the line 44 of Figure 2, with the casing construction omitted, the view depicting the operatin mechanism sectionally with the cross-section taken at right angles to the crosssection of Figure 3; a Figure 5 is a horizontal sectional view as seen along the line 55 of Figure 3; Figure 6 is a transverse sectional view as seen along the line 6-6 of Figure 3, and

Figure '7 is a central vertical sectional view on an enlarged scale showing the switch arranged for pull chain operation, being otherwise a section as seen alon the line 4-4 of Figure 2.

Similar reference characters refer to similar parts throughout the several views of the drawings.

The construction preferably comprises a casing generally indicated by the reference character 10 and a sub-assembly, better shown in Figure 4 and indicated generally by the reference character I I and comprising the mechanism accommodated within the casing Ill. The casing I0 may be of any desired cross-section and illustratively and preferably is of circular cross-section, providing internally a cylindrical space in which the mech-" anism II, as a single sub-assembly or entity, is

snugly received and therein housed. The casing ID, in the illustrative embodiment, comprises three casing sections, namely, a middle or central casing part l2 and two end casing parts l3 and 14 provided with any suitable means for relatively quickly and detachably securing them togethen Such means preferably comprises threaded connections and thus the casing part I2 is shaped at its respective ends to provide lesser-diametered flanges which are externally threaded, these threaded flanges being indicated at l5 and l 6, andeach end casing section [3 and I4 is counter-bored and internally threaded to provide female threaded parts I? and [8 into which the male threaded parts l and [B are respectively engaged. These threaded parts terminate in and have adjacent to them flat annular shoulders which mate upon threaded assembly of the parts and provide coactin-g annular faces for eifecting good frictional holding of the several parts in effect to lock the parts against too great ease of turning in unthreaded direction and thus maintain the three casing parts dependably assembled. The diameters and pitch of the various threaded parts are the same so that the end casing parts l3 and 14 are interchangeable and either may be threaded onto either end of the central casing part I2. Preferably these casing parts are made of any suitable molded and cured material such as Bakelite. As is clear from Figures 3 and 7 the internal diameters of the three casing parts are the same so that, regardless of which end casing part is assembled to which end of central casing part l2, the cylindrical space of each end casing part forms an extension of the cylindrical interior of the central casing part.

At a suitable point in the side of the central casing part i2 is provided a hole (Figure '7) into which leads the multi-conductor cable 2! (Figures 1 and 2) and preferably that hole is provided with a protective bushing 22 (Figure '7) suitably secured therein. The bushing may be of any suitable material, rigid such as metal, or cushioning or resilient, such as suitably vulcanized rubher. The various individual conductors of the cable 2| are, upon the inside of the casing, connected to suitable connecting devices embodied in the switch unit or sub-assembly H which, for purposes of illustration, is shown as constructed to handle at least five conductors, thus to illustrate application of my invention to a typical hospital signalling circuit in which the switch is to control four circuits of five conductors of which one is the common conductor to all of the circuits. The cable 2| may thus be a 5-conductor cable.

The sub-unit l I comprises a part 24 preferably of molded and cured resin or other plastic which may be said to be generally cylindrical (see Figure 6), excepting that it is shaped to provide laterally exposed vertically extending slots 25 which are five in number as shown in Figure 6, being rightangled in cross-section, and a sixth slot 26 which is preferably of curved cross-section, the six slots extending vertically and being equi-distantly spaced in the external and otherwise cylindrical face or side of the insulating member 24, thus leaving six vertically extending external ribs 2'! whose curved external faces fall in a geometric cylinder or surface of revolution whos diameter is somewhat less than the internal diameter of the casing 18, excepting at the upper ends thereoi where the diameter substantiall matches the internal diameter of the casing ll], thus providing in each vertical rib 21 a shoulder 28 (see Figures 3, 4, 6 and 7) at the upper end of the insulating member 24. At the lower end of the central casing part [2 the latter has an internal shoulder 29 (Figures 3 and '1) so that the insulating member 24, when inserted, with the parts assembled to it as later described, into the central casing part l2 and from the upper end of the latter as viewed in Figures 3 and 7, is brought to rest by the engagement of the shoulders 28 of the ribs 21 against the annular internal shoulder 29 of the casing part 12, giving the part 24 and the parts carried by it good mechanical support and also bringing it and them into co-axial relationship to the casing itself.

In each of the vertical external slots 25 is seated a contact spring 3! which extends upwardly be- 5 yond the upward cylindrical extension 24 of the part 24, being shaped and bent substantially as shown in Figures 3, 4 and '7, and overlying the contact spring is an elongated relatively stiff and heavy piece of sheet metal 32, and two spaced screws 33 and 34, extending through suitable holes in the two metal members 3! and 32, are threaded into suitable holes in the material of the insulating part 24 at the base of the slot, thus to secure these metal parts in the slot, one of the screws such as the lower one 34, being available for having a conductor from the cable 2| secured under its head and thus to extend the circuit of that conductor to the contact spring 3|. As is better shown in Figures 4 and '7 the contact springs 3i, five in number, are normally biased inwardly against the extension part 24 beyond which they project upwardly, being suitably bent inwardly toward the central axis, and at their ends being bent outwardly as at 3% for better coaction with a bridging or circuit-closing member 36 constructed and mounted and actuated as is later described. The upper ends of the metal plates 32 are bent away from the contact springs 3| to give them more ease of flexing radially outwardly when they are engaged and pressed outwardly by the contact member 36, upon depression of the latter.

The contact springs and their mountings and connector devices occupy the five slots 25; the sixth slot 26 (Figures 6 and '7) is of-substantial depth and is provided with curved walls so that the cable can be accommodated therein, the vertical slot 2% being closed by the casing walls. As is better understood from Figure 7 the cable, entering through the hole 20 or bushing 22, makes a downward bend as it is accommodated in the slot 26 and at the bottom end of the latter, the cable sheathing can terminate so that the five individual insulated conductors may, from that point on, be fanned out and led to the five binding screws 34 (Figure '7) for electrical connection. At its lower end, the part 24 has a downward cylindrical extension 24 (Figure '7) of reduced diameter, and it is about that extension that the five insulated conductors may be fanned or led to their respective binding screws 34.

In molding or shaping the part 24 it is provided with a central passage or hole along it axis, preferably shaped to have diiierent dimensions or cross-sectional shapes. Thus at the lower end of part 24 this coaxial channel or hole comprises a round or cylindrical portion 3? at the upper end of which it communicates with a square-crosssectioned channel 33 that is of substantial axial extent and which communicates at the upper end with a larger and circular recess or channel 39. Slidably fitted into the square channel 38 is a stem 4| of square cross-section which terminates at its upper end in a threaded stud 42. Ihe bridging contactor 33 is preferably in the form of a cup-shaped sheet metal stamping, having a flat base 36 and depending side walls 36' which are preferably arranged to form a hexagon (see Figure 6), so that each presents a fiat face for engagement with a contact spring 3|. The flat base portion 36 thereof has a hole in it (Figures 4 and 7) so that it is received over the threaded stud 42 to rest against the end face of the flat stem 4|, and superimposed upon the part 36 is 75 a hexagonal plate 43 of fiber or other insulating material, with its sides parallelingthe fiat sides 36 and. projecting beyond them as shown. Above the insulating plate 43 is a metal washer 44; parts 43 and 44 having central holes through which projects the threaded stem 42 which thus centers and coaxially aligns them with the stem and with the part 35.

These three parts are clamped tightly against the end face of the square stem 4| by the lower end of a metal stem 44 that is preferably of round cross-section andhas a threaded coaxial hole at its lower end for threaded engagement with the threaded stud 42. Surrounding the stem 4| and with one end abutting against the flat part 35 is a helical spring 45 whose lower end extends into the round portion 39 of the central hole or channel in part 24, abutting against the shoulder formed at the junction with the smaller square hole 38. Spring 45 normally biases the stem 4| and the parts carried by it in upward direction. The lower end of stem 4| is provided with suitable means for mechanically securing thereto, preferably detachably, a suitable pull or tension member which preferably takes the form of a chain 46 comprising hollow balls connected together by dumb-bell links, being a known form of pull chain, and in such case the connecting means comprises a sheet metal tubular or sleeve member 41 (Figures 4 and 7) of known form, having end walls or flanges each providing a central hole and with a radial slit that join a longitudinal side slit 48 which is narrow at its ends and enlarged centrally to permit the end ball link of the chain to be laterally snapped or pressed through the widened side slit and the dumb-bell link then passed through the narrower portion and through the radial slit in the end wall. The connecting element 41 may in turn be mechanically secured to the lower end of the square stem 4| in any suitable manner as by providing the lower end of stem 4| with a half dumb-bell or ball 1 terminus so that the member 41 can itself be readily and detachably secured to the stem.

The diameter of the round hole portion 31 at the lower end of the part 24 is larger than that of the tubular connecting element 41 and its axial extent is such that upon depression of the stem 4| against the spring 45 the tubular connector 41 loosely and freely slides through the hole portion 31 and is projected sufficiently beyond the lower end of the extension 24 so that the chain 46 may be easily attached to or detached from the projecting connecting device 41. The downward projection of the part 41 however is insufficient to permit disconnecting it from the ball stud 48 at the end of the stem 4i and hence, as will later be seen, there is no risk of the part 41 being inadvertently detached from the mechanism when it is desired to detach the chain 46 itself. As is now apparent the connecting element 41 is attached to the stem 4| during assembly of the latter to the part 24.

As is better shown in Figure 6, four of the external vertically extending ribs 21 are provided with longitudinal extending slots 50 located generally at the corners of a rectangle for the reception of elongated sheet metal posts 5| which are at their lower inner edges cut away as at 5| (see Figure 4) to provide an upper shoulder 5| and a lower shoulder 5 of which the former overlies the upper face of the part 24 and the latter is seated against a radially inward extension of the slot 50, and thereby eachpost 5| is held against longitudinal movement rela tive to the insulating part 24. The radial dimensions of the slot 5|] are such thatthe outer edges of the posts 5| fall in a geometric cylinder of the same radius as the radius of the internal walls of the casing part |2 Whose internal shoulder 29 is vertically slotted to accommodate the posts 5| which thus become keys which hold the insulating part 24 as well as the parts carriedby the posts 5| against rotary movement relativeto the casing.

The posts 5| may be stamped integrally with;

or suitably secured to, at their upper ends, a; frame plate 52 (Figures 4 and 7), the plate 52. being generally circular to be accommodated within the casing and being, by the posts 5|, held in a plane at right angles to the axis of V the insulating part 24 and coaxial with the axis received against the bottoms of recesses i5 and I |5 in the fiat upper annular end face of the male threaded part |5 of the central casing section l2. In thus seating in these recesses l5 and I5 the arms 54 and 55 also virtually key- Y the upper end of the sub-assembly or built-up frame structure against rotary movement relative to the casing and when either end casing,- part |3 or M is then screwed on to the threaded; male part I5, the shoulder therein closes over: the recesses l5 and I5, thus blocking upward[ movement of the sub-assembly relative to the casing and holding the shoulders 28 of the in sulating part 24 downwardly against the internal annular, shoulder 29 of the central casing part I2. If desired the parts can be so dimensioned that the horizontal portions of the arms 54 and 55 are somewhat clamped between the annular shoulder of the end casing part and the bottoms of their respective recesses.

The stem 44 is preferably of round cross-section and an intermediate portion is shaped, as by turning, to have a frusto-conical portion 51, and

at its upper end it has secured to it in any suit-f able way an elongated push-button 58 made preferably of any suitable non-conductive mate rial, for example, a molded and cured resin type. T of plastic, and in such case it may be molded onto a suitably configured upper end of the stem 44. The push member or button 58 thus becomes; related to' the square stem 4| at that end of the-! latter opposite to which the connecting device 41 for the chain 45 is provided. Accordingly a, I

depression'of the button 58 effects a downward{ movement of the stem 4| and the parts carriedl thereby just as does a pull of the chain 46.

Such downward movement brings the bridging member 36 into coaction with spring contacts. 3| in a manner later described and suitable means; are provided to lock or hold the bridging member- 36 in such downward or actuated position. Such; means preferably comprises two sliding plates; 62 and 63 which rest fiatwise on top of the frame plate 52 relative to which they are held and, slidably guided by a disc-like cover or guide-- plate 64 which is stamped to give it the shape of a widened inverted U, as is better shown in;

the Figure 3, thus providing it with two opposed) segment-shaped parts 64 and 64 (Figures 3 and! 5) which rest against the frame plate 52 to which: it is secured by bent-over cars 55 which are ac-..

ommodated in suitable peripheral recesses in the frame-plate 52, andthus providing a central parallel-sided plateportion 64 spaced upwardly from the frame plate 52 by somewhat more than the thickness of the two locking plates 62 and 63. In the-.iplate part 64 are two aligned elongated slots 66 and 61 through which project pins 68 and 69 respectively, being secured respectively by the cylindrical stem 44 toward which they 1 this latter action to take place during the use of the device, the studs and slots coacting to limit the plate movements during various steps of assembly of the switch unit ll of Figure 4.

to the sliding locking plates 62 and 63 to limit their movements toward or away from each other along the vertical diameter as viewed in Figure 5.

A helical spring 10 has elongated arms whose ends are looped around the upper grooved ends of the pins 68 and 69, and through the arms 51 of the stem 44. The frame plate 52 and the cover plate 64 are provided with central round holes large enough to accommodate the maximum diameter of the frusto-conical stem part 51 and in the position shown in the drawings, the cylindrical portion of the stem 44 below the cam portion 5'! extends-through these aligned holes, being engaged on opposite sides as shown in Figure 5 by the hook-shaped ends 62 and 63 of the locking plates. A felt washer H surrounds'that portion of the-stem 44 underneath the frame plate 52 and serves to cushion the upwardly moving parts, in effect snapped upwardly by the action of spring 45, when they are released for such upward movement as is later described.

As is better seen in Figures 4 and 7 the looking plates 62 and 63 have extensions 62 and 63 respectively which, in the assembly, extend beyond the frame plate 52 and at their outer ends If the device is to be employed for push button control by the patient or operator, the interchangeably mountable end casing sections [3 and I4 are'as'sembled to the central casing section l2 in the relation shown in Figures 1 and 3, casing part [3 being threaded onto the male threaded flange l5 of the central casing 12 and the other end casing part [4 being threaded onto the male threaded flange l6. Casing part l3 has an upper transverse end wall l3 spaced suitably from its lower end for purposes later described and in that end wall l3 is a hole l3 aligned with the axis of the casing section so that when the latter is-assembled as above described, the hole [3",

' which is slightly largerthan the cross-section have secured to them, as by molding them thereon, finger-pieces l2 and 13 respectively of Bakelite or the like, being preferably quite smaller in relation to the push button 53 that is carried by the stem 44. In relation to the sub-assembly or sub-unit II of Figure 4 these parts 12 and. 13'

are preferably at opposite ends of a, diameter and as the sub-assembly is inserted into the central casing section [2 by downward movement of the former into'the latter as above described,"

these finger pieces 12 and 73 ride downwardly into diametrically opposed vertical slots 14 and 15 respectively (Figure '7) which are formed in diametrically opposed portions of the upper end of the casing section l2, extending through the male threaded part l5 thereof and extending also into the main side wall of the section l2- below the threaded male part l5, as is better shown in Figure '7, so'that when an end casing part is screwed onto the threaded part 15 to its fullest extent, the finger piece parts 12 and [3 lie below the plane of the end edge of the finger piecesand are not interfered with by the end casing section. The finger pieces 12 and 13 being carried by the sliding locking plates 62, 63

which are biased outwardly away from each other of the elongated push button 58, the latter freely passes therethrough to be exposed on the outer side of the end wall 13 by a suficient extent for manual depression thereof. The other end casing part I 4 which in outer configuration may be tapered or curved off as shown in the drawings, has an internal end face I4 spaced from the upper end of the casing part l4 by a sufficient distance to just accommodate those portions of the sub-unit ll of Figure 4 which, when assembled to the central casing part l2 project downwardly below its lower end. Opening into the face l4 is a coaxial cylindrical recess [4' of a diameter equal to that of the hole' [3 in the' in a downward position. Thereby also the small finger pieces !2'I3 assume positions projecting from the casing l0, substantiall as in Figures 1, 2 and '7 so that the answering attendant can press them toward each other to separate the curved hooked edge portions 62* and 63 (Figure 5) and thereby permit the detent or ratchet-like part 51 to pass upwardly therethrough, under the urge'of spring 45, the felt washer H cushioning the stopping action of the frame plate 52 in limiting this upward movement of the parts, whereby the switch is restored to normal or open-circuit condition and the large plunger 58 is again projected out of the casing part [3 and is ready for subsequent actuation. It is to be noted that both finger pieces 12, 13 have to be actuated to effect this release from locked condition and thus there is obtained better assurance that the patient does not accidentally or unknowingly unlock the switch from signalling condition. The patient, knowing that the depression of a single button suffices to signal an attendant might inadvertently, after having initially set the switch by pressing the button 58, press one of the smaller buttons but that would not effect restoration of the switch and its circuits. In normal condition, that is Preferably the .move

with the large plunger or button 58 projected,

place, thedepression being simply against the biasing of the spring 10, and hence the release buttons operate as a tell-tale to indicate to the patient that, because" neither button is locked in depressed position, he is actuating the wrong actuator, for it is only the button 58 that remains locked in depressed position after actuation.

In cases where the patient is incapacitated to operate the button 58, or for other reasons, it is desired to provide the patient with a cord, string, chain or otherpull member, the end casing parts 13 and 14, instead of being assembled to the central casing part l2 as in Figures 1 and 3, are assembled thereto as shown in Figure '7 in that the casing part I4 is assembled to the upper end of the central casing part I2, by threading it onto the male threaded part 15, and end casing part I 3 is threaded onto the male threaded part l6 at the lower end of the central casing part l2.

The internal recess W of the casing part l4 thus receives therein the plunger or large'button 58, being of sufiicient axial extent to fully accommodate it when'it is in'normalor upwardly projected position. Button 58 is thus completely covered over and is, inaccessible for actuation, The

end casing part l4 may be provided with any Figure, '7, there is first secured to the lower end of the central sliding stem M the desired tension or pull member such as the'chain.4e,'and that is done in the manner above described, namev ,al"'insulating member 43 that overlies the conly, by effecting downward movementof the stem the insulating part 24 to facilitate connection thereto of the end ball link of the chain. The chainis then passed through the hole {3 which in the arrangement of Figure 3 serves to slidably guide and support the plungers58, whence. the casing part 13, may be screwedhome onto the j lower end of, the central .casing part, |.2:. The chain 46 mayv be of a length tog-reach to, the

patient or a.suitable cordoristring maybe tied to it and led to the point.fromfwhich it is de- Q. sired to actuate theswitchi, A singlepull-on the 4 10 or by the chain 46' in Figur 7. Rather the looking action takes place at a point intermediate of the complete range of movementof the stem structure, preferably a bit short of its maximum downward movement. In coaction with this relationship it ispossible to achieve a number of signal actuations subsequent to those achieved by the position of the switch whenrlocked against retrograde movement; For example, and as shown in Figures 3, 4' and 7, I may make one or more of the contact springs 3i, illustratively the one indicated at 35 shorter than the rest, or I may make one of the sides 36' (Figure 6) of the hexagonally side-walled contactor 36 shorter than the rest, or I may employ both in the same circuit other than the contact spring that is connected to the common; for example, contact spring 3| canbermade shorter as indicated and contact wall 36 with which the contact spring 31' ,coacts may be made shorter than the rest, as shown' In such case, when the structure is locked in downward position, all of the contact springs 3| are engaged by the contactor 36 and their circuits held closed, excepting contact spring 3| whose circuit thus remains open. But a subsequent additional downward movement of the stem structure -44, either by further depressing the button 58 in Figure 3 or by giving the chain 46 a slight additional pull, suffices to bring the parts 36 and 3| into engagement to closethat circuit which illustratively could be a lampsignal or a buzzermsignalso that. by repeated additional pushes orpulls by the patient the light may be. repeatedly flashed or the buzzer repeatedly buzzed.

At the same time it might be desirable during such subsequent or repeated additional pushes or pulls to deactivate one or more of the circuits initially closed when the switch is in locked position. One of the signals might comprise an electric lamp or buzzer or other audible signal at a diiTerent location and such signals though initial- 1y activated, can be repeatedlyfinactivated, thus ,4! to project the connecting sleeve or tube mem- I ber 41 out of the hole 31 in the lower end of r 0 walls 36 as is desired and corresponding toj the chain suifices to-depress the stem structure 4 l -44 sufliciently to pass the cam detent part 5l downl wardly below the plane of thetlocking plates 62 of the manual actuators and l? bythe at- ,tendant thereafter serve to restore the switch to Preferably the switch that the stem structure 4I-"144 is,not locked in s upwardly under the action of thespring 1 reemphasizing the signals as by repeatedly interrupting their circuits in response to such additi ona1 pullsor pushes. In such case the hexagontactor, 36 (Figures B, 4 and 7) can be made to project laterally beyond such of the contact; side circuit or circuits which it is so desired 'to repeatedly deactivate by subsequent actuations beyond the'locked condition of the switch. In Figures 3,, 4 and Ttheinsulating plate 43 i's'jshown projecting tothe right'beyond vthe right hand contact wall'of the partti? so that upon such additional downward actuation. this projecting, portied-engages thefu'pper' outwardly bent end of "the corresponding contact spring and cams it radially outward out of engagement with the contactor 36, thusbreaking the circuit of that contact springwhich of course should not be the contact to. which, the fcommon is connected if and 63 which .thereafter'serve to lock-theswitch i7 inactuated position,subsequent,depression of all 65 structure is -so .arranged P 7 the switch structure .is also to embody. a shortened contact spring 3!? or a shortened contact wall plate 36. On the other hand, in the ab- -sencei of sucha shortened contact arrangement,

camming of the.. common contact spring out of l engagement with the contactor 38, by the action 0. of aprojecting portionpf. the insulating plate j.. 343, can, if.desired,'be employed to accentuate the t.-signals thy, repeatedly deactivating M already se themU-Hf ,,However,j.f.with the preferredarrangement 9 shown in "the" drawings, and. above. described,

" greater, reliability offsignallingis achieved in fl that the subsequentadditional actuation,'"even "at the' other end, and'spring means adapted to if itopens one signalling circuit, eifects closure f; w

, constantly urgesaid shaft out of circuit closing i of another so that there 'is'no risk'jofc'om p1ete; failure of signalling if the button 58- of Figure 3 or the chain 46 of Figure? be inadvertently held ,p

ing parts having means for interchangeably so that the switch and stem structure, is held in its lowermost possible position. Maximumfdownward movement is preferably limited by the enf gagement of the lower edges of the side walls of the contactor 36 with the upper end face of the Q extension 24 of the insulating part 24 and when'j so engaged the lower end of the button or j V it will thus be'seen'thatthere has been prof 'vided in this invention a signalling switchwconstruction in which the various objects above set ture comprising" a' shaft adapted to be actuated by a push buttonfat one end and by'a pullchain position,' and said casing comprising'a central casing part andtwo end casing parts, said casconnecting said end ,casing parts to either end of said centralcasing part, one of said end casing parts'having an aperture therein adapted to chain depending upon. the, end of theicentral casing part to; which it is attached and. said plunger 58 is at rest just above the guide plate j jf other end casing'part adaptedto cover said push button andlsaid pull chain'dep'endingupm the end of the .central'casing' part to which itjis atforth together with many thoroughly'practical advantages are successfully achieved." The con- 1 struction is substantially fool-proof and is readily adaptable, by simple, speedy and convenient rearrangement of its parts, to suit it to meet A vvide1y difierin requirements of use met with in practice.

Asmany possible embodiments may, be] made of the above invention and, as many changes i might be made in the embodiment above set forth, it is to b e understood that all matter "hereinbefore set forth or shown'in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense. la m:

posed to engage anenlarged portion thereof to releasing'means for said locking means fcorn- I W prising a'projection on each of'said plates extending} laterally and opposite each other outside said' casing'whereby said portions adjacent said shaft may bejdisengaged from said enlarged portion thereof andsaid shaft released. ,7 '2. An electrical switch comprising a casing :j and a switch "structure therein, said switch structuracomprising fa reciprocating shaft 7 adapted to be actuatedlcby apush button at one tached and locking means for said shaftllateral to said shaft comprising a pair of 'platesfieach having a portion relatively adjacent s'a'idlshaft disposed to engage an enlargedportion thereof to hold it in circuit closing position and manual releasing meanscomprisinga projection on each .of said plates extending laterally and opposite each other beyond said, central, casinggpart wherebysaid portions adjacent said shaft may be disengaged from said enlarged portion'thereof. and said shaft. released.

4. An electrical. switch comprising, a ,casing e and a switch structure therein,.said switch structure comprising a shaft adapted to be actuated by a push button at one end and by a pull chain at the other. end, spring means, adapted to ,con-

stantly urge said shaft outof circuit closing position, latch means coacting with said shaft ,for. holding it in circuit opening position and manual' releasing'jmeansl comprising a. pair of oppositely disposed members projecting laterally from said switch structure for actuating said latch means to release said shaft, and said casing comprising a central casing part and two end casing parts, said casing parts having means for interchangeably connectin said end, casing v parts to either end of saidcentral casing part,

said central casing part having opposed openended slots at one end thereof foraccommodating said tvvo opposed laterally projecting release members upon assembly of said switch structure to said central casing part, one of said end casing D rts having an aperture thereinadapted to permit actuation of ,the push button and the pull chain therethrough depending upon the end of the central casing part to which it isattached and said other'end casing part adapted to'cover said push buttonand said pull chain depending end and by a pull"chain' at the otherjend a plu- I rality of electric contacts surrounding said shaft and adapted to be operated simultaneously thereby, spring means adapted to constantly 'urge said shaft out of circuit closing position, and locking means lateral to said shaft adapted 1 p to prevent said spring froim'returningsaid shaft to open circuit position comprising a pair of plates each having a portion relatively adjacent upon the end of the central casing part to which it is attached, said slots that accommodatesaid opposed release members being closed by that end casing part which is attached to that end of the central casing part.

5. An electrical switch comprising a jcasing and aswitchstructure therein, said casing comprising a tube-like central casing part and two end casingfparts for closing off the latter, said I said shaft disposed to engage an enlarged portion thereof to hold it in circuit closing p sition j and manual releasing means for said locking a means comprisingia'projection on each of said plates extending laterally and opposite each other outside said casing whereby said portions adjacent said shaft may be disengaged from said enlarged portion thereof and said shaft released. I

3-. e ec rical swit h c mp i a casing and'a switch structurethereirn said switch strucchain at the other end and in opposite direction by a spring means and havingcoacting electrical contactrneans for closing a circuit on: one

stroke of reciprocation of said shaft and for opening said circuit on the reverse stroke, said frame having a projecting frame part that seats against said ledge-like means to limit entry of said switch structure lengthwise into said tubelike central casing part, said casing parts having means for interchangeably connecting said end casing parts to either end of said tubular central casing part, one of said end casing parts having an aperture therein adapted to permit actuation of the push button and the pull chain therethrough depending upon the end of said tube-like casing part to which it is attached and said other end casing part adapted to cover said push button and said pull chain depending upon the end of the tube-like casing part to which it is attached, said switch structure being held against lengthwise movement away from said ledge-like means by whichever one of said end casing parts its attached to that end of said tube-like central casing part toward which said ledge-like means faces.

6. An electrical switch comprising a casing and a switch structure therein, said casing comprising a tube-like central casing part and two end casing parts for closing off the latter, said switch structure comprising an elongated frame received lengthwise into said central tube-like casing part and having therein a longitudinally extending reciprocating shaft adapted to be actuated in one direction by a push button at one end and by a pull chain at the other end and in opposite direction by a spring and having coacting electric contact means for closing a circuit on one stroke of reciprocation of said shaft and for opening said circuit on the reverse stroke, said casing parts having means for interchangeably connecting said end casing parts to either end of said tube-like central casin part, one of said end casing parts having an aperture therein adapted to permit actuation of the push button and the pull chain therethrough depending upon the end of said tube-like casing part to which it is attached and said other end casing part adapted to cover said push button andsaid pull chain depending upon the end of the tubelike casing part to which it is attached.

'7. An electrical switch comprising a. casing 14 and a switch structure therein, said casing comprising a tube-like central casing part and two end casing parts for closing off the latter, said tube-like casing part having an aperture in its wall for the passage therethrough of a conductor-carrying cable, said switch structure comprising an elongated frame received longitudinally into said central casing part and having therein a longitudinally extending reciprocating shaft adapted to be actuated in one direction by a push button at one end and by a pull chain at the other end and in opposite direction by a spring and having coacting electric contact means for closing a circuit on one stroke of reciprocation of said shaft and for opening said circuit on the reverse stroke, said frame having a longitudinally extending recess in a side thereof and underlying said casing aperture for accommodating said cable with the conductors thereof connected to said contact means, said casing parts having means for interchangeably connecting said end casing parts to either end of said tube-like central casin part, one of said end casing parts having an aperture therein adapted to permit actuation of the push button and the pull chain therethrough depending upon the end of said tube-like casing to which it is attached and said other end casing part adapted .to cover said push button and said pull chain depending upon the end of the tube-like casing part to which it is attached.

CHRISTIAN MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Curtiss Apr. 22, 1941" 

